From d88b67ea2f0e2e800d26191c7aa4cbfef425287f Mon Sep 17 00:00:00 2001
From: Matthew Rich <matthewrich.conf@gmail.com>
Date: Wed, 9 Oct 2024 22:40:47 +0000
Subject: [PATCH] add system pkg

---
 internal/system/os.go      | 126 +++++++++++++++++++++++++++++++++++++
 internal/system/os_test.go |  38 +++++++++++
 2 files changed, 164 insertions(+)
 create mode 100644 internal/system/os.go
 create mode 100644 internal/system/os_test.go

diff --git a/internal/system/os.go b/internal/system/os.go
new file mode 100644
index 0000000..76eb299
--- /dev/null
+++ b/internal/system/os.go
@@ -0,0 +1,126 @@
+// Copyright 2024 Matthew Rich <matthewrich.conf@gmail.com>. All rights reserved.
+
+package system
+
+import (
+	"os/user"
+	"strconv"
+	"regexp"
+	"log/slog"
+)
+
+var MatchId	*regexp.Regexp = regexp.MustCompile(`^[0-9]+$`)
+
+func LookupUIDString(userName string) string {
+	user, userLookupErr := user.Lookup(userName)
+	if userLookupErr != nil {
+		return ""
+	}
+	return user.Uid
+}
+
+func LookupUID(userName string) (int, error) {
+	var userLookupErr error
+	var UID string
+	if MatchId.MatchString(userName) {
+		user, err := user.LookupId(userName)
+		slog.Info("LookupUID() numeric", "user", user, "userLookupErr", err)
+		if err != nil {
+			userLookupErr = err
+			UID = userName
+		} else {
+			UID = user.Uid
+		}
+	} else {
+		if user, err := user.Lookup(userName); err != nil {
+			return -1, err
+		} else {
+			UID = user.Uid
+		}
+	}
+
+	uid, uidErr := strconv.Atoi(UID)
+	slog.Info("LookupUID()", "uid", uid, "uidErr", uidErr)
+	if uidErr != nil {
+		if userLookupErr != nil {
+			return -1, userLookupErr
+		} else {
+			return -1, uidErr
+		}
+	}
+
+	return uid, userLookupErr
+}
+
+func LookupGID(groupName string) (int, error) {
+	var GID string
+	if MatchId.MatchString(groupName) {
+		group, groupLookupErr := user.LookupGroupId(groupName)
+		if groupLookupErr != nil {
+			//return -1, groupLookupErr
+			GID = groupName
+		} else {
+			GID = group.Gid
+		}
+	} else {
+		group, groupLookupErr := user.LookupGroup(groupName)
+		if groupLookupErr != nil {
+			return -1, groupLookupErr
+		}
+		GID = group.Gid
+	}
+
+	gid, gidErr := strconv.Atoi(GID)
+	if gidErr != nil {
+		return -1, gidErr
+	}
+
+	return gid, nil
+}
+
+func LookupGIDString(groupName string) string {
+	group, groupLookupErr := user.LookupGroup(groupName)
+	if groupLookupErr != nil {
+		return ""
+	}
+	return group.Gid
+}
+
+func ProcessUser() *user.User {
+	processUser, userErr := user.Current()
+	if userErr != nil {
+		panic(userErr)
+	}
+	return processUser
+}
+
+func ProcessGroup(u *user.User) *user.Group {
+	if u == nil {
+		u = ProcessUser()
+	}
+	processGroup, groupErr := user.LookupGroupId(u.Gid)
+	if groupErr != nil {
+		panic(groupErr)
+	}
+	return processGroup
+}
+
+func ProcessUserName() string {
+	processUser, userErr := user.Current()
+	if userErr != nil {
+		panic(userErr)
+	}
+	return processUser.Username
+}
+
+func ProcessGroupName() string {
+	processUser, userErr := user.Current()
+	if userErr != nil {
+		panic(userErr)
+	}
+	processGroup, groupErr := user.LookupGroupId(processUser.Gid)
+	if groupErr != nil {
+		panic(groupErr)
+	}
+	return processGroup.Name
+}
diff --git a/internal/system/os_test.go b/internal/system/os_test.go
new file mode 100644
index 0000000..553d573
--- /dev/null
+++ b/internal/system/os_test.go
@@ -0,0 +1,38 @@
+// Copyright 2024 Matthew Rich <matthewrich.conf@gmail.com>. All rights reserved.
+
+
+package system
+
+import (
+	_ "context"
+	_ "encoding/json"
+	"github.com/stretchr/testify/assert"
+	_ "io"
+	_ "net/http"
+	_ "net/http/httptest"
+	_ "net/url"
+	_ "strings"
+	"testing"
+)
+
+func TestLookupUID(t *testing.T) {
+	uid, e := LookupUID("nobody")
+
+	assert.Nil(t, e)
+	assert.Equal(t, 65534, uid)
+
+	nuid, ne := LookupUID("10101")
+	assert.Error(t, ne, "user: unknonwn userid ", ne)
+	assert.Equal(t, 10101, nuid)
+}
+
+func TestLookupGID(t *testing.T) {
+	gid, e := LookupGID("adm")
+
+	assert.Nil(t, e)
+	assert.Equal(t, 4, gid)
+
+	ngid, ne := LookupGID("1001")
+	assert.Nil(t, ne)
+	assert.Equal(t, 1001, ngid)
+}